"The Abominable Mystery" that puzzled Charles Darwin during his last years of life

According to the English naturalist, it was a "most disconcerting phenomenon", which threatened the foundations of his maximum scientific contribution: evolutionism.

Evolution through natural selection only occurs through the accumulation of small, successive and favorable variations, "explains Darwin in the book" The Origin of Species ", published in 1859.

Therefore, "it can not produce significant or sudden changes, it can only act in short and slow stages".

But two decades after writing his famous book, this deep conviction that "nature does not leap" quaked in the shadow of an "extraordinary" event in history.

Darwin expressed his frustration about this in a series of letters sent to various colleagues from 1875 until his death in 1882.

One of these letters, written 140 years ago to English botanist Joseph Hooker, tackled the subject with such a drama that has marked generations of biologists.

"I just read (John) Ball's essay.It's quite daring," says Darwin in a letter dated July 22, 1879 regarding an investigation by an Irish naturalist about the flora of the European Alps.

"As far as we can judge," he continues, "the rapid development of all the higher plants of recent geological years is an abominable mystery."

Yes, the "abominable mystery" does not concern a strange monstrous creature, but flowering plants.

Intellectual honesty

William Friedman, a professor of evolutionary biology at Harvard University in the United States, wrote an essay in 2009 on this "legendary" letter, stating that "no other group of people in the United organisms has captured Darwin's attention in such dramatic terms "Flowering Plants

"Of all the big groups of plants, flowering plants are the ones that have emerged most recently on Earth," Friedman told BBC Mundo.

The problem is that, according to Ball's findings, this occurrence has occurred abruptly and skipped, such as its diversification.

Darwin himself went on to badert that "the sudden appearance" of flowering plants was bewildering "for all those who believe in any form of evolution, especially for those who believe in an extremely progressive evolution" .

This group, formerly known as angiosperms, appeared about 130 million years ago and has managed to diversify into 300,000 species, becoming the most diverse of the plant kingdom.

"When you think of your garden, most are flowering plants, and when you think of the fruits or vegetables you eat, most are flowering plants," says Friedman.

"Therefore, the mystery is somewhat exacerbated by the fact that it is a very diverse and dominant group in our lives," he adds.

And Darwin was clear.

"The best thing about Darwin, is that he's very intellectually honest," Friedman said. In his letters, "he says he's not going to sweep (and hide) the subject under the rug, which really makes him crazy."

"Become the daisies"

The problem of the origins and diversification of angiosperms did not bother Darwin but was "the most extreme exception" to his theory of evolution, explains Friedman.

"One possible theory is that flowering plants were created miraculously, that is, they support the other explanation of the origin of life on Earth," says he in reference to creationism.

Harvard's Arnold Arboretum director adds: "In other words, they are not the product of an evolutionary process, but of a god who simply said," Boom! Make the daisies. Boom! Make the herbs. Boom! Become magnolias, and so on. "

According to the fossil record of that time, there was no doubt that it had been so fast.

But Darwin raised another possible explanation.

The lost continent

In the famous letter to Hooker, the English naturalist states: "I imagined that for long periods, there would have been a small isolated continent in the southern hemisphere, where the upper floors were born."

Although he himself qualifies this conjecture as "miserably poor," he is relying on a reality that he has learned over his almost five years traveling the world aboard HMS Beagle.

"We constantly overestimate the perfection of the geological record and we mistakenly infer that, as some genera or families have not been discovered at a certain stage, they did not exist before this stage," writes Darwin in " The origin of species ".

"We are constantly forgetting how big the world is compared to the region where geological formations have been carefully examined," he continues.

"We forget," he continues, "that species groups have existed for a long time elsewhere and are multiplying slowly before invading the ancient archipelagos of Europe and the United States."

That is to say, Darwin thought that over time, fossil evidence would seem to show that flowering plants were evolving so slowly.

"He did not solve the mystery, but he understood," according to Friedman. "He is betting on empiricism, rational thinking and universal laws rather than miracles."

The mystery today

"I would like this whole problem to be solved," Darwin agrees to Hooker in his letter.

However, "he did not live long enough to see that he was right," says Friedman, whose research focuses precisely on the origin and subsequent diversification of angiosperms.

"We have discovered some very important fossils that have helped us understand the first few sentences of flowering plant diversification and we have made great progress, especially over the past 30 years," he said.

And although his evolutionary puzzle includes more pieces, the researcher recognizes that "there are still many things we do not know."

In fact, one of the simplest questions that persist is to know where the basic structure of the flower comes from.

"We are still convinced that the origins and diversification of flowering plants did not happen quickly and that nature does not skip," Friedman said.

"But the abominable mystery itself continues."

BBC